1. Field of the Invention
The present invention relates to a method for the non-destructive stretching and fastening of pelts on a pelt board, for which is used a machine of the kind which comprises holding means for engagement of the lower end of a respective pelt board and gripping elements for securing the lower end of a pelt applied loosely on said pelt board during the stretching of the pelt on said board, where the pelt board is placed in the holding means, and where the gripping elements comprising inner parts and outer parts are brought into engagement with the pelt by the introduction of the inner parts between the surface of the pelt board and the leather side of the pelt, and the outer parts opposite the inner parts are displaced towards the fur side of the pelt for securing the pelt between the inner parts and the outer parts, and where the stretching takes place by effecting a displacement between the gripping elements and the holding means for the lower end of a relevant pelt board, and where an effective fastening of the pelt in the stretched position on the pelt board is established by the drawing of a holster-like bag (fixing bag) over the fur side of the pelt, which at least over a part of the lower end of the pelt (the tail end) is brought into tight contact with the fur side of the pelt, followed by a releasing of the gripping elements from the pelt and a releasing of the holding means from the distension element, and a stretching machine for the execution of the method.
2. Description of Related Art
In the drying of pelts, for example, a mink or a fox pelt (in the following referred to jointly as a pelt), after skinning and scraping off the layer of fat on the leather side of the pelt, the pelts are stretched, for example, on a pelt board which is often first provided with a fat-absorbing material, the object being that, during the drying of the pelt, the fat remaining on the leather side of the pelt will be drawn into the paper and hereby removed from the pelt.
In the following, some definitions are provided which will be used in the specification and claims.
The mounting of pelts is to be understood as a procedure which comprises the drawing of a pelt over a pelt board, preferably with the leather side of the pelt facing towards the surface of the board, the stretching of the pelt on the pelt board and the fastening/securing of the pelt in the stretched position on the pelt board.
The use of pelt boards in connection with the drying of pelts is well-known, and with the passing of time, a great number of configurations of such pelt boards has been developed with the view of improving the drying of pelts. With the mechanization and organizing of production and sale of pelts which has taken place, there has also occurred a certain standardization of pelt sizes, and herewith, also of the pelt boards on which the pelts are stretched and fixed in this position during the drying, the object being to be able to achieve the best possible and uniform pelt quality, which means that the producers can obtain a higher price for the pelts.
Those pelt boards which have become most widespread, and which today are used by the majority of the producers of pelts, including in particular mink pelts, are made of wood, and can briefly be described as a flat piece of wood with a first broadside surface and a second broadside surface, and a first narrow side surface and a second narrow side surface, the breadth of which is essentially considerably less than the breadth of the broad side surface, and where the one end of the board (the foot end) is cut off at right-angles to the longitudinal axis of the board, and the lower end nearest the foot end has constant breadth, but hereafter this breadth gradually decreases towards a pointed but rounded end part (the front end, the nose end), and where the pelt board has a through-going slot between the first broadside surface and the second broadside surface, said slot lying symmetrically around the longitudinal axis of the board and extending between near the pointed end part and at least for over a half of the length of the board.
The pelt board described above is a pelt board intended for the pelts from male animals, which are normally larger than the pelts from female animals. A pelt board intended for use in the drying of the leather side of pelts from female animals does not comprise a lower end where the breath of the board is constant.
The “nose end” of the pelt shall be understood to be that part of the pelt which previously covered the cranium of the furred animal, and in connection with the mounting of the pelt is that part of the pelt which is placed in/over the pointed but rounded end of the board, which can randomly be referred to as the front end or the nose end of a pelt board.
The “tail end” of the pelt shall be understood as that end of the pelt where the tail sits firmly and from where the tail extends from the lower edge of the back, and which collectively can denote the whole circumference of the pelt in said area. In the mounting of the pelt, the tail end of the pelt is always placed nearest the foot end of the board.
The lower end of the back of the pelt shall be understood to be that part on both sides of the area where the tail extends from the lower edge of the back of the pelt.
The belly side of the pelt shall be understood to be that side of the pelt where the forelegs and thighs are placed.
In the following, a “mounted” pelt shall be understood to be a pelt drawn onto a pelt board where it is stretched and fixed in this position on the board.
In the following, the removal of the pelt from the pelt board, typically after the conclusion of the drying process, is to be understood as the removal of a pelt which has been stretched and fixed in this position on the board during the drying process. The procedure for removal also includes the removal of any elements which may have been used for the fixing of the pelt in the stretched position on the pelt board.
In certain cases, the fat-absorbing material which is placed on the board before the drawing-on of the pelt is a bag made of fat-absorbing material, preferably of fat-absorbing paper with perforations, for example, in the form of a so-called “pelt bag,” which will thus be lying between the pelt board and the leather side of the pelt.
The drying procedure or drying of pelts shall be understood to be a drying-out of the leather side of the pelt to a preferred extent which from experience excludes oxidation and the attack on the pelt by mites. The drying process is typically effected by the blowing of dry air in the slot in the board via pipes which are introduced into the slot and via the perforations in the walls of the pelt bag, so that the dry air is diffused out to the leather side of the pelt and dries the pelt.
In the drawing of the pelt on to the pelt board, a stretching of the pelt is often effected mechanically in order to achieve the greatest possible length of the pelts, and herewith the highest obtainable price at the fur auction.
The hitherto most used method of mounting a pelt is that of manually drawing the pelt over the pelt board with the leather side facing the board, which is then inserted into a machine comprising holding means for fastening of the board's lower end, which extends below that part of the board which is covered by the pelt, i.e., after the pelt has been stretched on the board by the machine. Hereafter, the gripping elements are inserted into engagement between the leather side and the fur side of the pelt on the back and the belly side respectively, after which the pelt is stretched out on the board by a relative displacement between the gripping elements and the board, after which the pelt is fastened in the stretched position on the board by the insertion of staples/clips which penetrate the pelt and are anchored in the board itself.
Then, the pelt is dried while stretched on the board, which gives rise to elongated holes in the pelt from the clips/staples which secure the pelt to the board. The result is that the holes, which appear both in the back of the pelt, which is the most valuable part of the pelt, as well as the belly part, make the pelt in these areas worthless, in that this part of the pelt with the holes can not be used in the further processing of the pelt. Thus, the placing of the clips/staples so close to the under edges of the pelt, without the pelt drawing itself free of the clips during the drying with further damage to the pelt, is important. Stretching machines have been developed for this purpose, which are known from Danish Patent DK 169525, which discloses a stretching machine comprising gripping elements and sensors which control the extent of the stretching of the pelt on the board, so that the optimal stapling can take place without tearing out of the staples.
In the removal of the pelt from the board, the stapling of the pelts gives rise to the need for manual labour to a not inconsiderable degree in connection with the removal of the staples, in that the removal of the staples must take place without any further damage to the pelt. Finally, the use of staples/clips for the fixing of the pelt results in damage to the material of which the board is made, which is most often wood so that, after a time, the board must be replaced.
The ideal method for stretching and drying of the pelt will thus involve being able to fix the pelt in the stretched position without the use of staples. From International Patent Application Publication WO-A1-0162985, there is known a method and a fixing bag for fixing of the pelt in the stretched position during the drying whereby, after the pelt has been stretched on the board, a bag is drawn over the fur side of the pelt, the inside dimensions of said bag being such that the outwardly-directed forces of the fur side of the pelt press the leather side of the pelt so much against the board that the pelt is thereby secured in the stretched position, without the use of staples which penetrate both the pelt and the board. The above-mentioned reduction in the value of the pelt as a result of holes is thereby avoided, which means that it will be possible to achieve an appreciably higher price for the pelt.
Danish Patent Application DK 2000 01174L describes a method and machine for the stretching of pelts, where the machine is arranged with gripping elements in a manner which enables a fixing bag to be drawn over a pelt which is stretched on a traditional board by the machine, where the holding elements comprise flat beak-shaped holding elements which respectively grip the back part and the belly part (the leg side) of the pelt from below, which means that the fixing bag can be drawn over the pelt to a level below the lower edge of the back part.
However, practical use of this method has shown that the pelt shrinks on each side of the tail root during the drying, which often results in a reduced price for the pelts as a consequence of the pelt not having the expected size after the processing. The reason for this is partly that the fixing bag can not exert enough pressure against the fur side of the broad sides of the pelt for sufficient friction to arise between the surface of the board and the leather side of the pelt to counteract the slipping of the above-mentioned sides of the pelt. The result is that use is still made of a smaller number of staples for the fixing of said slipping parts of the pelts during the drying process, the reason being that the price reduction per pelt at a lower size category is greater than the price reduction for the few holes left in the pelt by the staples.
A solution to this problem could be to stretch the pelts somewhat longer on the boards, but the known pelt machines do not offer adequate facilities for a preferred stretching of the pelt on the boards where, with the holding elements of the known pelt machines, a counter-hold is established during the stretching of the pelts along two relatively narrow engagement surfaces on one or both of the flat sides of the pelt, with the result that, if the pelts are stretched to a greater degree, they will be damaged in the holding areas, which are also the most valuable parts.
In the meantime, a further development has taken place of the pelt boards which are used in connection with the stretching, fixing and drying of pelts, so that it is possible to achieve an effective fixing of the pelt during the drying process without shrinking/slipping of parts of the pelt's lower ends.
Roughly speaking, the further development consists of configuring the broad sides of the pelt boards in an arched/concave manner in relation to the centre axis of the board, whereby a better counter-hold force is achieved on the areas of the stretched pelt, which experience has shown will give way when use is made of the traditional boards. This configuration of the boards has thus made it possible to fix the pelt in the stretched position on a pelt board during the drying without the use of staples which leave holes in the pelt. These types of boards are sometimes referred to as distension elements and in the description below and in the claims, all references to pelt boards in the context of the present invention are intended to encompass distension elements which are not necessarily boards.
However, this further development of the boards has meant that the known stretching machines, which are intended for use together with the traditional boards described above, which consist of a planar board of pinewood with two opposing broad side surfaces and two narrow side surfaces, are not usable.
Moreover, there has further been a wish to be able to carry out a stretching of the pelts to a degree which is greater than has traditionally been possible, cf. the problems described above.